Variable stroke pump



June 1944- B. w. GRIMSL EY VARIABLE STROKE PUMP Filed July 1, 1945 ZW/il/ is Q 5611 fl ifiji INVENTOR; I

AT'I'EI RNEYS Patented June 6, 1944 Bewly wor msiey, Louisville, Ky. *fAnn lnl t s alii -it ii ff." l ;v

' (c1. 1os ss 7 v Claims;

My invention relates to Diesel engine srand other internal combustion enginesof the fuel injection type, and has among its objects and ad vantages the provision of an improved fuelinjectionpump embodyinga novel cam meansio'r 5 imparting a variable stroke to the pump plunger. said means imparting .a desirable change in phase relation of the camming to the crankshaft of the internal combustion engine.

Inthe accompanying drawing: my 10 Figure 1 is an end view, and

Figure 2 is a sectional view along the line 2--2 of Figure 1.

In the embodiment of the invention selected for illustration, the pump l8 comprises a base I2 having side walls I4 interconnected by a top wall l6. Upon the wall I6 is mounted a pump body l8 having a bore within which is slidably mounted the pump plunger 22.

A valve controlled fluid inlet conduit 24 has 0 communication with the bore 20. A similar conduit 26 is provided for the fuel forced from the bore 28. A stem 28 is attached to the plunger 22 and is provided with a head 30 engageable by a cam 32. Between the head 30 and a plate 34 attached to the body I8 is interposed a compression spring 35 for yieldingly urging the head against the cam 32. The plate 34 is in the nature of a split washer which slidably guides the stem 28 and acts as a stop for the plunger 22, so that 30 the plunger stroke will always begin at the same point.

The cam 32 is fixedly related to a driven gear 38 meshing with a drive gear 38. The gear 38 is fixed to a drive shaft 40, and the driven gear 36 may be oscillated about the axis of the drive gear 38 for adjusting the cam 32 to different positions for varying the plunger stroke and advancing or retarding the cam action. Links 42 are pivotally connected with the shaft 48 and with a shaft 44 to which the driven gear 36 and the cam 32 are fixedly connected. The links guide the gear 36 for movement in a path concentrically of the gear 38.

Means for adjusting the cam 32 comprises a 45 link 46 pivotally connected with the shaft 44 and with a body 48. This body is provided with a dovetail 58 slidably guided between dovetail flanges 52 on the base I 2. An adjusting screw 54 has a swivel connection with the body 48, as

at 5B, and is threaded through a lug 58 fixed to the base I 2. This screw parallels the base l2, while the link 46 may be pivoted to different angular positions from its coaxial position with the plunger 22, to raise and lower the cam 30,

thereby varying thefstroke of the plunger and the ph'asecam;v i V The driv gear 38 1's rotated counterclockwise when viewingFigure The drawing illustrates a pump wherein the plunger has a maximum stroke of one-half inch, and inwhich the, gears36 and 38. have diametersof twoinches. V g I The mpuntingof thedriven gear andthe cam is. a r n cm e inrelation t th l er 22, either towardthe, plunger or away from it, in an arc concentrically of the drive gear 38. The bottom of the plunger stroke is always the dead part of the cam in full load position. Pulling the cam 32 downwardly shortens the plunger stroke. When the driven gear 36 is in the top position for ful1 load, the angle formed by the cam and its shaft support is for a one-half inch stroke. To retard the engine to three-quarter load, the cam is dropped one-quarter of the distance which then permits three-quarters of a plunger stroke, in addition to advancing the injection, since the angle of the cam and its support now approximates 86. In dropping the cam to a zero load position, the cam angle is 76. This results in a phase change in advence of 90 to 76". It is Well known that the injection must be advanced as the engine speed is lowered. My invention may be constructed so that the angle of the cam and its support will give the required change. The angle is altered by changing the drive and driven gears to greater or lesser diameters. The plunger is spring loaded and the bottom of its stroke is the dead side of the cam in the fully advanced position.

This pump is of exceedingly simple and durable construction, in addition to being easily operated. The large camming surface increases its resistance to wear. Positive control of injection timing or phase change is automatically provided. This means of changing timing relations is adaptable to many mechanisms, such as the timyieldingly biased against said cam; a rotary drive means, a rotary driven means: opratively engaging said drive means and flxedto said cam, and means for oscillating said driven means 4. A fuel injection pump comprising a body having a bore and an outlet communicatin therewith, a rotary cam, a plunger operating in said bore to force fuel through said outlet and yieldingly biased against said cam, a rotary drive means, a rotary driven means operatively engaging said drive .means and fixed to said cam, said drive means and said driven means each comprising a gear, a rotary shaft having the driven gear, and said cam: fixed; thereto, a link means pivotally connected with'saidshaft and mounted for pivotal movement about the axis of said drive means, a second link pivotally connectabout the axis of said drive means to, change the phase of said cam with respect to said"'drive" means. V.

3. A fuel injection pump comprising. a body; having a bore and an outlet communicating therewith, a rotary cam, a plunger operatinginj said bore to forcefuel through said outlet and yieldingly-biased against said cam, a rotary drive means, a rotary driven means opermvay enggaging said drive means and fixed to; said cam, said drive means and saiddri-ven means each comprising a gear, a iii-1kinean's' supporting said driven gear for'oscillation aboutthe axis of the drive gear, and a "sc'r actuated-means for pivoting said link means about the axis ofsaid drive means for-changingthephase of said cam withrespect' to said'drive'gear.

edwi th said shaft, a body mounted for sliding movement in a path at right angles to said plunger, said second link being pivotally connected with said body, and screw means for adjusting said body to oscillate said driven gear, the cam andsaid shaft about the axis of the drive gear to vary the stroke of said plunger.

- 5'. In a pump having a reciprocating plunger, 9. rotary' drive means, a cam for actuating' said plunger, a driven-means fixed to said cam and operativel-y engaging said drive means, and'a support for said driven means and said cam mount ed for oscillation about the axis of said drive means to oscillate'the driven means and said cam ab'ut'said-drive means to vary the 'timing'of the plunger.

' BEWLEY W. GRIMSLEY, 

